9,184 research outputs found

    Ground-state phase diagram of the Kondo lattice model on triangular-to-kagome lattices

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    We investigate the ground-state phase diagram of the Kondo lattice model with classical localized spins on triangular-to-kagome lattices by using a variational calculation. We identify the parameter regions where a four-sublattice noncoplanar order is stable with a finite spin scalar chirality while changing the lattice structure from triangular to kagome continuously. Although the noncoplanar spin states appear in a wide range of parameters, the spin configurations on the kagome network become coplanar as approaching the kagome lattice; eventually, the scalar chirality vanishes for the kagome lattice model.Comment: 7 pages, 3 figure

    Global attractors for doubly nonlinear evolution equations with non-monotone perturbations

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    This paper proposes an abstract theory concerned with dynamical systems generated by doubly nonlinear evolution equations governed by subdifferential operators with non-monotone perturbations in a reflexive Banach space setting. In order to construct global attractors, an approach based on the notion of generalized semiflow is employed instead of the usual semi-group approach, since solutions of the Cauchy problem for the equation might not be unique. Moreover, the preceding abstract theory is applied to a generalized Allen-Cahn equation whose potential is divided into a convex part and a non-convex part as well as a semilinear parabolic equation with a nonlinear term involving gradients

    Stability of non-isolated asymptotic profiles for fast diffusion

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    The stability of asymptotic profiles of solutions to the Cauchy-Dirichlet problem for Fast Diffusion Equation (FDE, for short) is discussed. The main result of the present paper is the stability of any asymptotic profiles of least energy. It is noteworthy that this result can cover non-isolated profiles, e.g., those for thin annular domain cases. The method of proof is based on the Lojasiewicz-Simon inequality, which is usually used to prove the convergence of solutions to prescribed limits, as well as a uniform extinction estimate for solutions to FDE. Besides, local minimizers of an energy functional associated with this issue are characterized. Furthermore, the instability of positive radial asymptotic profiles in thin annular domains is also proved by applying the Lojasiewicz-Simon inequality in a different way

    New trends in active filters for improving power quality

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    Since their basic compensation principles were proposed around 1970, active filters have been studied by many researchers and engineers aiming to put them into practical applications. Shunt active filters for harmonic compensation with or without reactive power compensation, flicker compensation or voltage regulation have been put on a commercial base in Japan, and their rating or capacity has ranged from 50 kVA to 60 MVA at present. In near future, the term of active filters will cover a much wider sense than that of active filters in the 1970s did. The function of active filters will be expanded from voltage flicker compensation or voltage regulation into power quality improvement for power distribution systems as the capacity of active filters becomes larger. This paper describes present states of the active filters based on state-of-the-art power electronics technology, and their future prospects toward the 21st century, including the personal view and expectation of the author</p

    Sellars on Functionalism and Normativity

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    The term ‘functionalism’ is usually heard in connection with the philosophy of mind or cognition. The functionalism of Wilfrid Sellars, however, is in the first instance as response to the worries about the metaphysics not of mental states, but of meaning. Only late in his career did Sellars explore the possibility of extending his functionalism into an account of cognition. It has been suggested, though, that Sellars’ extension of his functionalist theory into subpersonal territory is not successful. In particular, there is a worry abroad that in order to be a functionalist about cognitive states, Sellars must succumb to a special form of the Myth of the Given. In this essay I will review and elucidate what I take to be the structure of Sellars’ functionalism, defending it from this worry. I will suggest a resolution of some apparent textual contradictions based in part on the chronology of Sellars’ writing, with the assumption that later writings express Sellars’ more nuanced views. Draft of 2009

    Suppression of common-mode voltage in a PWM rectifier/inverter system

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    This paper proposes a PWM rectifier/inverter system capable of suppressing not only supply harmonic currents but also electromagnetic interference (EMI). An active common-noise canceler (ACC) developed for this system is characterized by sophisticated connection of a common-mode transformer which can compensate for common-mode voltages produced by both PWM rectifier and inverter. As a result, the size of the common-mode transformer can be reduced to 1/3, compared with the previously proposed ACC. A prototype PWM rectifier/inverter system (2.2 kW) has been implemented and tested. Some experimental results show reduction characteristics of the supply harmonic current and EMI</p

    The clinical epidemiology of hysteria: vanishingly rare, or just vanishing?

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    Vanish 1. intr. To disappear from sight or become invisible, esp. in a rapid and mysterious way (Shorter Oxford English Dictionary, 1972). There is a well-known view that hysteria has virtually disappeared in the Western world. There are two versions of this argument: one is that there was never a clinical disorder that coincided with the diagnosis, and hysteria has now been reconstructed as something else (e.g. Micale, 1993). The other is that hysteria did exist but has now become much rarer than it was (most famously, Veith, 1965). According to this view, hysteria is to be found in patients from developing countries, but in Western countries it is ‘virtually a historical curiosity’ (BMJ 1976). It is the latter view that is – in our experience – most commonly held by our colleagues in general psychiatry. Yet, this opinion is not shared by those who are involved in the clinical care of patients with neurological disorders: ‘to a psychiatrist who sees patients on the medical and surgical services of a general hospital, it appears that hysteria remains a rather common phenomenon’ (Brownsberger, 1966). A number of descriptions from liaison psychiatry services support this opinion (Akagi & House, 2001). There are good reasons why it might be difficult to judge just how common (or rare) hysteria really is. Epidemiology depends on reliable case definition, case ascertainment and selection of a suitable population to study (Neugebauer et al. 1980), and each of these poses problems in the study of hysterical disorders
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